Passage-travelling device

ABSTRACT

A self-propelling device ( 1 ) is adapted to travel through a passage ( 3 ) having walls containing contractile tissue, the device ( 1 ) comprising a body ( 2 ) and at least one contractile tissue-stimulating means for stimulating the walls to urge the device selectively in both a forward direction ( 7 ). The stimulating means may be electrodes ( 5,8 ), and the passage can be the gut of an animal or human. The device is particularly useful as an enteroscope.

This application claims priority to PCf/GB00/03023, filed Aug. 3, 2000,published on Feb. 8, 2001, Publication No. WO 01/08548 A1 in the Englishlanguage and which claimed priority to GB Patent Application No.9918184.4, filed Aug. 3, 1999.

FIELD OF THE INVENTION

The present invention relates to a device, capable of propelling itselfalong a passage having walls containing contractile tissue.

BACKGROUND ART

Electrical stimulation has been extensively used as a method of inducingcontraction of strips of muscular tissue. Further, direct smooth musclestimulation has also been used to improve emptying of ileal and colonicpouches in animals and humans.

In addition, UK patent application 9808426.2 describes a device, such asan endoscope, having means for propelling itself along a tortuouspassage by way of suction means. The means comprises a first suctionmeans mounted on the endoscope and a second suction means mountedthereon for movement with respect to the first suction meanslongitudinally of the endoscope, the first and second suction means eachbeing arranged, when actuated, to grip the tissue of a body passage inwhich the endoscope is disposed.

French Patent Application No. 2,237,648 discloses a device capable ofbeing placed in the lower digestive tract as a suppository and whichcomprises means for agitating the walls of the tract to clearobstructions during constipation. The agitating means can operate eithervia electrical stimulation of the tract, by imparting mechanicalvibrations to the tract, or by imparting an effect due to the liberationof a gas under pressure.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, a device isprovided that is adapted to travel through a passage having wallscontaining contractile tissue the device comprising a body and at leastone contractile tissue stimulating means for urging the device in aforward or backward direction.

According to a second aspect, the present invention provides a method ofpropelling a device along a passage having walls containing contractiletissue, comprising stimulating contractile tissue in the walls so as tocontract the wall in contact with the device, and so urge the device ina forward or backward direction.

Preferred features of the invention will be evident from theaccompanying dependent claims.

The present invention will now be further described in the followingnon-limiting examples as illustrated by the accompanying drawings inwhich:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 represents a device, according to one embodiment of theinvention, in which the stimulating means comprises a pair of electrodeslocated at the rear of the body of the device;

FIG. 2 illustrates a second embodiment of the present invention, inwhich a pair of electrodes is located both at the rear and front of thebody of the device; and

FIG. 3 illustrates a third embodiment of the present invention, which issimilar to that shown in FIG. 2, but where no umbilicus is attached tothe device.

BEST MODE

Whilst the passage through which the device (1) travels may be anypassage containing contractile tissue, a particularly useful applicationof the device is for investigation of the gut of animals or humans.Thus, in FIG. 1 a self-propelling device (1) is shown comprising a body(2) adapted to travelling within a gut (3) of an animal or a human in aforward direction (7). On the body (2) are located stimulating meanswhich, in FIG. 1, comprises a pair of electrodes (5). These are locatedtoward the rear of the device on a tapered portion. In operation, theelectrodes (5) electrically stimulate the smooth muscle of the gut (3)wall which contracts around only one end of the device and so squeezesthe body (2) along the passage, in a similar way that naturalperistalsis propels a bolus of food.

Thus, when a voltage is applied to the electrodes (5), a current flowsthrough the wall of the gut (3) causing the smooth muscle tissue of thewall to contract around only the end of the device near the electrodes(5) and so squeeze the device (1) forwards. As the device is squeezedforwards new wall tissue is brought into contact with the electrodes(5), and so this new tissue is, in turn, electrically stimulated and socontracts to squeeze the body (2) of the device (1). The devicetherefore advances smoothly along the passage so long, as a stimulatingvoltage is applied. In this way, generalised autonomic peristalsis isnot stimulated, but instead the local muscles and nerves of the gut aredirectly stimulated, to produce a local contraction, which is propagatedby the electrodes as the device travels along the passage.

Under certain circumstances it may be preferable to view the tissueswhen they are inflated. Inflating the tissues may prevent a reliableelectrical contact from being made but, were this to happen, the problemcan be overcome by stimulating the tissues prior to inflation so as toadvance the device. Once the device (1) has advanced sufficiently faralong the passage, for example the colon or small bowel, the current maybe switched off and the bowel inflated so that it can be viewed with acamera, the device (1) being pulled progressively back by an umbilicus(4).

Preferably, the body (2) has a substantially tapered rear portion, sothat the body (2) is, for example, lozenge-shaped, hence allowing theforward movement (7) to be smooth. However, any shape of body (2) willsuffice as long as the device will be urged forwards when squeezed bythe gut as it contracts. Thus, the body (2) may have a shape similar tothat of a rugby ball or to a cylinder with hemispherical ends. Indeed,the body (2) may also be in the form of an inflatable balloon withexternal electrodes (5,8) that can be inserted in an uninflated statethrough a small orifice into a larger part of the gut or passage, inwhich it is subsequently inflated ready for travel.

The umbilicus (4) may be arranged so that it can transmit informationfrom the device (1) to a remote station, for example a screen viewed bya doctor. The nose (6) may comprise any one or more of a camera means, alight means and means for supplying air or water to inflate the passage.The device may also be used to carry objects such as feeding tubes,guide wires, physiological sensors or conventional endoscopes within thegut.

The body (2) may also comprise a rear chamber in which the umbilicus (4)can be stored and gradually paid out as the device (1) travels forward.

Generally, the electrodes (5) receive a voltage of between 2 and 10V,more preferably 3 and 5V, at a frequency of 3 Hz to 20 kHz, morepreferably 10 Hz to 30 Hz.

As previously mentioned, the rear portion of the body (2) is typicallytapered in shape with respect to the longitudinal axis of the body (2),and preferably at a taper angle of between 5° and 80° half angle, andpreferably between 10° and 45° half angle, since such angles give a goodcompromise between ease of squeeze and ease of progress.

The body (2) is preferably constructed to have a length appropriate tothe passageway in which it will travel. For example, in the human smallbowel a length of between 1 and 5 cm, preferably between 2 and 4 cm, anda width of between 0.5 and 3 cm, preferably between 1 and 2 cm, would beappropriate.

A second embodiment is shown in FIG. 2, in which a second pair ofelectrodes (8) are located on the front , or nose, end of the device'sbody (2). This second pair of electrodes (8) can be used to stimulatethe gut (3), instead of the first pair of electrodes (5), to allow thedevice (1) to travel in a backward direction. Under certaincircumstances, it may be desirable to lock the device (1) in one place,in which case, all electrodes (5,8) can be activated simultaneously, sothat the device (1) is enclosed by contracted tissues.

In FIG. 3, a third embodiment is illustrated in which an umbilicus isabsent, but instead a transmitter/receiver unit (9) is located in thebody (2) allowing an operator at a remote station to communicate, andthus operate, the device (1). The absence of umbilicus necessitates thepresence in the body (2) of an independent power source (10), forexample a known type of battery. Electric current can thus be suppliedto either pair of electrodes (5,8) according to the desired direction oftravel.

A particularly attractive feature of the device described above is thatit is very useful in enteroscopy, that is, the inspection of the smallbowel. Enteroscopy has until now remained difficult, since the smallbowel in the gastrointestinal tract is mostly inaccessible to standardendoscopy. This is because either the endoscopist must push an endoscopefrom the caecum or the duodenum, or he must slowly allow naturalperistalsis to push an extremely flexible endoscope down through thedigestive tract, so that he can observe the walls of the small bowel asthe endoscope is pulled backwards.

Neither of these approaches is satisfactory, since the technicaldifficulties of such pushing only allow the ends of the small bowel tobe investigated, whilst the long time (several hours) allowed to pass astandard endoscope is most unpleasant and impractical.

Thus, the device as described above, which is capable of carrying asmall camera and a light source both rapidly and smoothly through thesmall bowel is of considerable benefit.

What is claimed is:
 1. A device adapted to travel through a passagehaving walls containing local contractile tissue, the device comprisinga body and at least one contractile tissue-stimulating means to urge thedevice selectively in both a forward and backward direction; wherein atleast a rear-most portion of the body, in relation to a requireddirection of travel, is substantially tapered with respect to alongitudinal axis of the body, and has located thereon said at least onelocal contractile tissue-stimulating means.
 2. A device as claimed inclaim 1, wherein the contractile tissue-stimulating means is adapted tostimulate either smooth or striated muscle.
 3. A device as claimed inclaim 1, wherein the body is lozenge-shaped, or shaped substantially asa cylinder with hemispherical ends, or is an inflatable balloon capableof assuming a required shape upon inflation.
 4. A device as claimed inclaim 1, wherein the tapered body has an angle of taper of between 5°and 80° half angle.
 5. A device as claimed in claim 1, wherein the bodyhas a length of between 1 and 5 cm.
 6. A device as claimed in claim 1,wherein the width of the body is between 0.5 and 3 cm.
 7. A device asclaimed in claim 1, further comprising an umbilicus attached to one endof the body, said umbilicus being capable of transmitting information toa remote station.
 8. A device as claimed in claim 1, wherein the deviceis without attachment to any means passing out of the passage.
 9. Adevice as claimed in claim 1, having at least means for transportingobjects selected from the group consisting of: feeding tubes, guidewires, physiological sensors and endoscopes.
 10. A method of propellinga device along a passage having walls containing contractile tissue,comprising: providing a device according to claim 1 within the passageand activating the device to stimulate local contractile tissue in thewalls of the passage, so as to contract a local region of the walls incontact with one end of the device, and so urge the device selectivelyin both a forward and backward direction.
 11. A method as claimed inclaim 10, wherein the device is a discrete unit that is operated from aremote station.
 12. A method as claimed in claim 10, wherein the deviceis an enteroscope.
 13. A passage-traveling device adapted to travelthrough a passage having walls containing contractile tissue, the devicecomprising a tapered body, a plurality of electrodes disposed on thebody, and means for supplying an electric current selectively to saidelectrodes and thereby to contractile tissue surrounding either one endof the body to urge the device selectively in both a forward andbackward direction.
 14. A device as claimed in claim 13, wherein saidplurality of electrodes are located on either end of the body in anorientation relative to the body that is opposite to that of a requireddirection of travel.
 15. A device as claimed in claim 13, wherein thebody is associated with at least one selected from the group consistingof a camera means, a light means, means for supplying air or water toinflate the passage, means for storing energy to be supplied to theelectrodes as electrical current, and means for receiving ortransmitting data to a remote station.
 16. A moveable, remotely-operableenteroscope comprising a discrete, tapered body; and at least one localcontractile tissue-stimulating means configured to urge the enteroscopeselectively in both a forward and backward direction and located, on thebody, in an orientation relative to the body being opposite to arequired direction of movement of the enteroscope.